One key to more effective vaccines is better delivery of antigen to rare antigen-presenting cells, known as dendritic cells. Current efforts to deliver vaccines to dendritic cells entail: a) individualized ex vivo procedures that are costly, or b) adjuvants that activate innate immunity with inflammation that could result in unacceptable toxicity. Our goal is to develop a simple, safe and inexpensive, topical vaccine delivery system that targets dendritic cell precursors in the epidermis called Langerhans cells. Lancell's approach is to deliver antigen to large numbers of Langerhans cells and induce them to migrate to draining lymph nodes where they can activate naive T cells. In Phase I, we developed a quantitative assay that is sensitive and directly measures immunogenic peptides associated with Langerhans cells after their migration to skin draining lymph nodes. The proposed Phase II studies will optimize each parameter of our vaccine delivery system for the induction of tumor immunity in a murine model system. PROPOSED COMMERCIAL APPLICATION: Nearly 1.5 million new cases of cancer are diagnosed in the U.S. annually, and virtually all of these patients are candidates for an effective tumor immunotherapy. Tumor-associated antigens continue to be identified, but there is a need for more immunogenic vaccines. Lancell, L.L.C. is developing a vaccine delivery system exploiting epidermal Langerhans cells that is designed to be simple, potent and cost-effective.